1. Field of the Invention
This invention is in the field of steam generators and devices and safety devices for interrupting the flow of energy to the heating element.
2. Description of the Prior Art
Steam cookers have a plurality of cooking compartments heated by means of steam flowing from a steam generator. A separate pressure vessel for generating the steam includes an electric element located therein. The heating element will fail in the event a sufficient amount of water does not surround the heating coil or element. The heating element is relatively expensive and is difficult to replace. As a result, various means have been provided to minimize such failures. Typically, a glass tube located outside of the vessel is connected via conduits in fluid communication with the vessel, thereby allowing for a visual indication of the level of water within the vessel. Such visual indicators may be located in remote positions and, therefore, may not provide a sufficient warning to the operator. Further, the operator is busy with various tasks and does not pay sufficient attention to the water level, resulting in eventual burnout of the heating element. In order to solve this problem, commercially available water level sensors have been mounted to extend into the vessel, measuring the level of the water therein. Such a probe is typically connected to a relay coil having contacts positioned in the electric line connected to the heating element. Thus, once the water level falls below the sensor, the relay coil will be activated, opening the coil contacts and interrupting the flow of electrical energy to the heating element.
Many of the prior steam generators utilize a mechanical float in lieu of electrical sensors for detecting the level of water within the pressure vessel. The float is then operable to disconnect the flow of energy to the heating element once the water level falls below a specified elevation. Such mechanical floats quickly develop scale buildup, resulting in inoperable level detectors and eventual failure of the heating element.
Despite the prior safety precautions, failures still occur of the heating element. The aforementioned low-water sensors extend into the pressure vessel and are exposed to a great volume of water and steam, resulting in scale buildup on the sensor, causing eventual failure of the sensor. Further, the probe is exposed to considerable heat within the vessel, resulting in a deterioration and eventual failure of the probe or sensor.
In order to solve the aforementioned problems, I have added a backup safety probe or sensor along with associated relay contacts to interrupt the flow of electrical energy to the heating element. Most importantly, I have located the backup, low-water sensor outside of the main pressure vessel in a conduit in fluid communication therewith, thereby reducing the scale buildup and deterioration of the backup sensor.